The synthesis, crystal structure and Hirshfeld surface analysis of the thiophene derivatives 5-(phenylsulfonyl)-5,6-dihydrobenzo[4,5]thieno[3,2-j]phenanthridine and (E)-N-{2-[2-(benzo[b]thiophen-2-yl)ethenyl]phenyl}-N-(prop-2-yn-1-yl)benzenesulfonamide

The crystal structures of two benzothiophene derivatives are described along with an analysis of the intermolecular contacts in the crystals performed using Hirshfeld surface analysis and two-dimensional fingerprint plots.

In both compounds, the molecular structure is stabilized by weak C23-H23Á Á ÁO1 intramolecular interactions (Tables 1  and 2)  The molecular structure of compound II, with atom labelling. Displacement ellipsoids are drawn at the 30% probability level. Intramolecular contacts are shown as dashed lines (Table 2). Table 1 Hydrogen-bond geometry (Å , ) for I.  Table 2 Hydrogen-bond geometry (Å , ) for II.

Figure 1
The molecular structure of compound I, with atom labelling. Displacement ellipsoids are drawn at the 30% probability level. Intramolecular contacts are shown as dashed lines (Table 1).

Hirshfeld surface analysis
A recent article by Tiekink and collaborators (Tan et al., 2019) reviews and describes the uses and utility of Hirshfeld surface analysis (Spackman & Jayatilaka, 2009) and the associated two-dimensional fingerprint plots (McKinnon et al., 2007) to analyse intermolecular contacts in crystals. The various calculations (d norm , curvedness and shape index and 2D fingerprint plots) were performed with CrystalExplorer17 (Turner et al., 2017).
The Hirshfeld surfaces of compounds I and II mapped over d norm are shown in Fig. 5. They are colour-mapped with the normalized contact distance, d norm , from red (distances shorter than the sum of the van der Waals radii) through white to blue (distances longer than the sum of the van der Waals radii). The d norm surface was mapped over a fixed colour scale of À0.085 (red) to 1.564 (blue) for compound I and À0.286 (red) to 1.374 (blue) for compound II. The red spots indicate intermolecular contacts involved in hydrogen bonding.    (Table 1), and H atoms not involved in hydrogen bonding have been omitted.

Figure 5
The Hirshfeld surfaces of compounds I and II, mapped over d norm  The full two-dimensional fingerprint plot for compound I, and fingerprint

Synthesis and crystallization
Compound I: A solution of N-propargylbenzenesulfonamide (0.50 g) in xylenes (20 mL), MnO 2 (0.50 g) was added and the reaction mixture was refluxed for 24 h. It was then filtered through a celite pad and washed with hot xylenes (2 Â 10 mL). The combined filtrate was concentrated under vacuum and then triturated with MeOH to afford dibenzo[b]thiophene (0.38 g, 92%) as a dull white solid. Finally, compound I was crystallized using ethanol.
(1.2 g, 3.069 mmol) in CH 3 CN (10 mL), K 2 CO 3 (0.63 g, 4.603 mmol) and propargyl bromide (0.54 mL, 4.603 mmol) were added and the mixture was stirred at room temperature for 12 h. After completion of the reaction (monitored by TLC), it was poured into crushed ice (50 g) containing conc. HCl (5 mL), extracted with ethyl acetate (2 Â 20 mL) then washed with water (2 Â 20 mL) and dried (Na 2 SO 4 ). Removal of the solvent in vacuo followed by crystallization from methanol (4 mL) afforded compound II as a white solid.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 3. H atoms were found difference electron-density maps and positioned geometrically. They were refined as riding, with C-H = 0.93-0.94 Å and Uiso(H) = 1.2Ueq(C) or 1.5Ueq(Cmethyl).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq C1 0.1532 (